Desks are of practicability, so they are widely used in offices and homes. The desks are made of wood in the past. As people attach more importance to ecological environment, the wood acquired from deforestation is replaced by a plastic board. The existing desk which is made of plastic boards, a reinforcing steel beam is fixed on the bottom-surface of desk top, the upper end of the desk leg is connected with a reinforcing steel beam. The drawbacks of said desk are as following: 1. A reinforcing steel beam is fixed on the bottom surface of desk top, so it is a waste of material, and the cost of manufacture is high, the weight of desk top is increased; 2. the desk top is hollow, so its intensity is weak; 3. the upper end of the desk leg is connected with the reinforcing steel beam, the connecting strength is weak, and the connection structure is not removable.